MART-1/Melan-A

Melanoma antigen recognized by T-cell 1 (MART-1), also known as Melan-A, is a transmembrane glycoprotein involved in the normal synthesis of melanin, which is mainly present in melanocytes. As a diagnostic indicator of melanocytic lesions, Melan-A is mainly used in the differential diagnosis of melanocyte derived tumors (+) and non-melanocyte tumors (-). Especially, it often combines with S100 and HMB-45 for the differential diagnosis of malignant melanoma (MM). Moreover, Melan-A is easily recognized by T lymphocytes in tumor tissues, which may induce strong antitumor responses, indicating that Melan-A has the potential to become a valuable target in MM immunotherapy. Meanwhile, Melan-A can be expressed in adrenocortical tumor but not in adrenal pheochromocytoma and renal cell carcinoma. In addition, the positivity of Melan-A, HMB-45, and SMA in smooth muscle like cells is the diagnostic evidence of hepatic angiomyolipoma, indicating that tumor cells have the bidirectional differentiation potential between smooth muscle cells and melanocytes.